Reliability Assessment Of Aero-engine Spindle Bearings

Aero-engine spindle bearings is an important support components of aero-engine. It works at poor working conditions, it is easy to fail. It is result that aircraft engine can’t work normally, and plane crash is brought. So it is of great significance to research reliability of aero-engine spindle bearings. Firstly, the development situation of aero-engine spindle bearings at home and abroad is introduced in this article. Work characteristics and failure mode of aero-engine bearing is summarized, every failure mechanism of bearings failure mode is studied. Effective solutions are put forward for each failure mode, reliability of aero-engine bearings is improved. It has important reference value for maintenance and design of aero-engine bearings. According to bearing failure reason, fault tree of bearings is established by using the principle and method of fault tree.Then, the reliability evaluation index of bearings is introduced. According to the law of bearing life obeyed Weibull distribution, all kinds of evaluation methods of bearing life will be studied from the bearing life obeys two parameter Weibull distribution and three parameters Weibull distribution. It mainly includes maximum likelihood estimation, best linear invariant estimation, best linear unbiased estimation, least square method, Newton iteration method and correlation coefficient optimization method, and the scope of each method is summarized. According to bearing has characteristics of high reliability, high cost, small sample size and expensive testing costs, the evaluation of small sample data is introduced. Reliability of bearing is estimated with method of Bayesian point estimation. The weighted least squares method is utilized to estimate shape parameter and scale parameter of Weibull distribution in the case of no failure. The bearing cumulative failure function, failure rate and average life can be gotten. The bearing experiment data is used to verify the validity of small sample evaluation.Finally, according to the evaluation method of bearing reliability, the system of bearing reliability evaluation is developed by MATLAB 2010a software.It is proved that it has an important value for the design,replacement and maintenance of aero-engine bearings.